Liner puller



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June 23, 1970 D. A. LEWALLEN LINER FULLER 2 Sheets-Sheet 2 S w 2V INVENTOR ATTOR KEYS DmV/EL A. LE/VALLEM Ar a/W),

Filed Dec.

United States Patent 3,516,143 LINER PULLER Daniel A. Lewallen, P.O. Box 312, Jonesboro, La. 71251 Continuation-impart of application Ser. No. 571,102, Aug. 8, 1966. This application Dec. 19, 1967, Ser. No. 691,784

Int. Cl. B23p 19/04 US. Cl. 29-234 7 Claims ABSTRACT OF THE DISCLOSURE A device for pulling liners from oil well pumps and the like comprising an elongate center shaft with a hydraulically operated piston reciprocably received for extension from one end and a rod received reciprocably for extension from the other end thereof, a plurality of arms pivotally secured to the rod which extends from the other end of the center portion and slidably and pivotally secured to the center portion extending along the sides of the center portion by means of a threadably mounted sleeve on the center portion for engaging a liner and for pulling the liner out of a cylinder is disclosed.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of application Ser. No. 571,102, filed Aug. 8, 1966, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention Although the device of the instant invention is not so limited, it has been found particularly advantageous in the removal of liners from reciprocating mud pumps of the type used in the oil field. Oil field mud pumps generally comprise one or more pressure cylinders adapted to receive liners having internal diameters of varying size, a piston mounted for reciprocable movement in the liner, a suitable valving arrangement for receiving low pressure fluid and discharging high pressure fluid, and means for transmitting power to the piston. The liners of pumps of this type are periodically changed, not only to remove worn liners, but also to control the volumetric and pressure discharge of the pump. Those well skilled in the art will realize that the use of a larger bore liner will give the pump a high volumetric capability at relatively low discharge pressures while a smaller bore liner will decrease the volumetric capability of the pump but increase the discharge pressure. It is necessary to change pump liners during the drilling of a well since the volume of drilling mud and discharge pressure will vary as depth increases. Generally, a large quantity of mud at relatively low pressures is needed during the first part of the drilling operation while a smaller volume of mud at higher pressures is needed as the well deepens.

Accordingly, the liners of oil well reciprocating pumps are often changed several times during the drilling of a well to provide the optimum balance between mud volume and discharge pressure to maximize the drilling rate. Pulling pump liners is an arduous time-consuming chore usually performed when the rig is shut down for other reasons, such as waiting for cement to set on a surface or long string of casing that has been placed in the hole. The normal procedure for moving liners from a pump is to remove the bolts afiixing the cylinder covers to the pressure cylinder and removing the covers. The pump piston is then dismantled and removed from within the liner. A force supplying device is then affixed to one end of the cylinder and operated to force the liner through the cylinder and out the other end. A new liner,

or one of different internal diameter is then inserted into the cylinder with the pump being reassembled in reverse order.

Description of the prior art The general concept of liner pullers is known in the prior art since considerable difficulty has been encountered by those skilled in the relevant art in providing an adequate puller for liners of this type. Exemplary of the prior art devices are United States Pats. Nos. 2,487,902, Stout et al.; 2,613,983, Knudson; and 2,924,005. Wilson et al. One common approach, in the prior art, has been to provide a device which may be connected to a piston rod and engaged with the liner such that the piston rod itself pushes the liner out. Since pistons are designed for relatively rapid reciprocation and the associated crankshaft and the like is also designed for rapid rotation, this approach has not been totally successful because it is usually necessary to move the liner very slowly and carefully out of the cylinder so as to avoid scoring the liner and the cylinder. This is especially true since there is usually a very high coefficient of sliding friction between the external surface of the liner and the internal surface of the cylinder. This type of approach is exemplified by the Wilson patent. It has also been proposed simply to provide some means for engaging the liner and utilize any source of power, such as hand power or a jack of some sort for removing the liner. This approach is embodied in the Knudson patent. Another approach has been to use the piston itself as a means for moving the liner out of the cylinder and to engage the inside of the cylinder by means of gripper jaws. This approach has been embodied in the Stout patent wherein the gripper jaws are forced against the internal surface of a cylinder by means of a hydraulic device. This inven tion has never been accepted because it destroys the liner and renders it useless for further service. This is especially acute in the oil well industry where the liners are repeatedly used and are often changed to get the proper degree of flow and pressure for pushing mud down a well.

The present invention is distingiushed from the prior art in that it provides a single integral puller which needs no auxiliary source of power and which quickly and safely removes liners from cylinders in oil field pumps and other engines and pumps.

SUMMARY Briefly, the device of the instant invention comprises a tool for insertion into one end of the liner for pulling the liner from the cylinder by engagement of lip of arms with end and edge of liner opposite point of insertion. Structurally, the instant invention comprises an elongate support, a plunger mounted for telescopic movement with the support, and a plurality of outwardly pivoted arms mounted on the support and the plunger such that extending the plunger with respect to the support moves the arms outwardly into engagement with the end of the liner opposite from the point of insertion. In addition, the connection between the outwardly movable arms and either the support or the plunger is slidable to allow the outward pivotal movement. An extensible arm is preferably mounted in the support for selective actuable movement into engagement with the pump for exerting the forces necessary to remove the liner from the pressure cylinder.

It is accordingly an object of the instant invention to provide a liner puller which may be inserted into one open end of a pressure cylinder and actuated for movement into engagement with the opposite end of the liner such thata pump liner may be removed from its housing without damage to the liner or the cylinder from which it is removed.

Another object of the instant invention is to provide a liner puller having a plurality of outward movable arms each of which is provided with a means, to engage the outer edge of the liner, at the end opposite point of insertion, the arms being outwardly movable upon an operators moving a telescoping plunger.

Still another object of the instant invention is to provide a liner puller of the type described having a plurality of outwardly movable arms pivotally mounted on the support and the plunger, one of the pivotal mounting means providing for the slidable movement of the arms therethrough.

A further object of the instant invention is to provide a liner puller which is compact, inexpensive to manufac ture, easy to operate and which is durable and long-lasting.

Other objects and advantages of the instant invention reside in the combination of elements, arrangements of parts and features of construction and operation, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawing wherein there is shown a preferred embodiment of this inventive concept.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the liner puller of the instant invention illustrated as disposed in a pressure cylinder shown in dashed lines.

FIG. 2 is an enlarged general longitudinal cross-sectional View of the liner puller of FIG. 1.

FIG. 3 is a cross-sectional view of the pressure cylinder and liner puller shown in FIG. 1, taken substantially along line 3-3 thereof as viewed in the direction indicated by the arrows.

FIG. 4 is an enlarged transverse cross-sectional view of the liner puller of FIG. 2, taken substantially along line 4-4 thereof as viewed in the direction indicated by the arrows, illustrating the collar adjustably mounted on the support for pivotally and slidably mounting the outwardby extending arms.

FIG. 5 is an enlarged transverse cross-sectional view of the puller of FIGS. 2 and 4, taken substantially along line 5-5 of FIG. 2 as viewed in the direction indicated by the arrows, certain parts being broken away for clarity of illustration.

FIG. 6 is a transverse cross-sectional view of the liner puller of FIG. 2 taken substantially along line 6-6 thereof as viewed in the direction indicated by the arrows, illustrating the pivotal connection between each of the movable arms and the telescoping plunger.

FIG. 7 is a side view in partial cross section of an improved, strengthened and simplified embodiment of the invention.

FIG. 8 is a side cross-sectional view of the hydraulic plunger of the embodiment of FIG. 7 taken substantially along lines 8-8 in the direction of the arrows as shown in FIG. 7.

FIG. 9 is an end view partially in cross section showing the means for connecting arms to the reciprocable rod taken substantially along lines 9-9 in the direction of the arrows as shown in FIG. 7.

FIG. 10 is an end view in partial cross section showing the pivot collar threadably received on the central section taken substantially along lines 10-10 in the direction of the arrows as shown in FIG. 7.

DESCRIPTION OF THE PERFERRED EMBODIMENTS Referring now to FIGS. 1 through 6 of the drawing in detail, wherein like reference characters designate like elements throughout the several views thereof, there is shown generally at 10 a pump comprised of a cylindrical pressure chamber 12 positioined on a base or foundation 14 and closely frictionally receiving a pump liner 16. Pump 10 also includes a pressure head (not shown) covering the end of chamber 12 and secured thereto by a plurality of bolts (not shown) extending through a plurality of apertures 18 in a flange 20.

A liner puller constructed in accordance with the principles of the instant invention is shown generally at 22 and has as its major components a central support designated generally at 24, a telescoping plunger shown generally at 26, a plurality of outwardly movable arms denominated generally at 28, means illustrated generally at 30 pivotally mounting the ends of arms 28 onto plunger 26 and means shown generally at 32 pivotally and slidably mounting arms 28 on support 24. A force applying mechanism shown generally at 34 is preferably mounted on support 24 for forcing liner 16 out of chamber 12 at the command of an operator. In the use of puller 22, mounting means 32 will be moved along support 24 guiding arms 28 in a radial pivotal path until the desired spread of arms 28 is achieved. Plunger 26 will be grasped and extended by an operator thereby sliding arms 28 through mounting means 32 and diminishing the spread of the terminal ends of arms 28. Liner puller 22 will be inserted into liner 16 until adapter ring 111 contacts the pressure flange (at end nearest point of insertion) of stuffing box of pump (not shown), force is then applied, causing terminal ends 62 of arms 28 to come into contact with end and edge 98 of liner 16. A suitable force is then applied on support 24 and on mechanism 34, by the insertion of pressurized fluid (air or liquid) through inlet 110 to extract liner 16 from chamber 12.

Support 24 is a generally tubular exteriorly threaded support 36 forming axial passageways 38, 40 at each end thereof separated by a partition 42. An outwardly extending flange 44, 46 may be provided on each end of tube 36 after the installation of mounting means 32 to prevent means 32 from inadvertently sliding 01f either end of support 24.

Plunger 26 includes a cylindrical rod 48 reciprocably and rotatably mounted in passageway 40 by a press fit bushing 50 located adjacent the outlet end thereof. An enlarged cylindrical boss 52 is positioned in passageway 40 on the end of rod 48 providing an abutment for a helical spring 54 engaging bushing 50 at the other end thereof, biasing plunger 26 into a retracted position with respect to support 24. An enlarged knob 56 is afiixed on the outer end of rod 48 providing a convenient grasping means for an individual. It will be readily apparent that plunger 26 may be reciprocated out of support 24 by pulling on knob 56.

Each of arms 28 includes a cylindrical bar 58 cut-away as at 60 to form a shoulder 62 providing a liner engaging means illustrated in operative relation in FIG. 1. Bar 58 is connected to plunger 26 by mounting means 30 shown best in FIG. 6. Mounting means 30 includes a substantially Y-shaped block 64 having a central opening 66 receiving rod 48 therethrough and fixedly holding it therein by any conventional manner as by the provision of a circumferential weld 68. Each of the arms of block 64 forms a substantially U-shaped slot 7 0' loosely receiving the end of bar 58 therein. A transverse fastener shown generally at 72 aflixes one of the bars 58 in each slot and comprises a bolt 74 extending through slot 70 and bar 58 having a nut 76 completing the connection. It will be apparent that slot 70 is of a sufficient depth to allow considerable pivotal movement of arms 28 as illustrated best in FIG. 2.

Mounting means 32 interconnects arms 28 and support 24 allowing for relative movement therebetween and for the pivotal movement of arms 28 independently of supof aligned screws 90 having a conical point 92 extend through block 78 into a conical recess 94 formed in rocker 86. A pair of set screws 96 extend through a portion of block 78 at right angles to screws 90 in engagement therewith thereby preventing inadvertent dislodgement thereof.

It is readily apparent that bar 58 is slidable through aperture 88 and that rocker 86 may pivot about the axis of screws 90. It will therefore be seen that the extension of plunger 26 with respect to support 24 slides bar 58 through mounting means 32 with any necessary pivotal movement being accommodated by rocker 86. Accordingly, the extension of plunger 26 lessens the angular relation between arm 28 and support 24. This is accomplished since the trapezoid defined by mounting means 32, that portion of plunger 26 between mounting means 32 and mounting means 30 and that portion of arm 28 between mounting means 30, 32, retains a constant perpendicular distance at mounting means 32 and mounting means 30 as the other legs of the trapezoid increase in length. It should also be noted that the position of mounting means 32 on support 24 controls the spread of arms 28 when plunger 26 is in the retracted position.

When it is desired to insert liner puller 22 into chamber 12 to remove liner 16, the operator first measures the internal diameter of liner 16 to determine the required spread of arms 28. The operator then threadably advances mounting means 32 along support 24 until rocker 86 is aligned with a selected one of indicia 57 on one of arms 28 which acts to designate the spread of liner engaging means 62 corresponding to the internal diameter of liner 16. This movement is accomplished by rotating mounting means 32, arms 28, mounting means 30 and plunger 26 as a unit along support 24 until rocker 86 is aligned with the desired indicia. For example, if the internal diameter of the particular liner is five inches, the operator will advance mounting means 32 into alignment with the indicia marked which effects the spacing of base 98 of shoulder 62 two and one-half inches from the axis of support 24. Although the threaded engagement of tube 36 and mounting means 32 act to maintain the desired position of mounting means 32 this feature may, of course, be effected in other ways. For example, support 24 and opening 80 may be machined to such a tolerance that mounting means 32 is slidable only upon the application of considerable force or a set screw (not shown) may be pro vided through block 78 to secure mounting means 32 at a desired location.

The operator then grasps support 24 with one hand and knob 56 of plunger 26 with the other and forcibly extends plunger 26 thereby lessening the angle between arms 28 and support 24 to such an extent that liner puller 22 may be easily inserted into liner 16. After liner puller 22 is inserted through liner 16 (FIG. 1), the operator relaxes the forces on plunger 26 thereby allowing spring 54 to return plunger 26 to the retracted position. During the movement of plunger 26 toward the retracted position, arms 28 slide through openings 88 with rocker 86 accommodating the necessary pivotal movement. At this stage of the liner pulling operation, it is necessary only to subject support 24 to a force in the direction of the arrow in FIG. 1 to remove liner 16 from chamber 12.

Although it should be apparent that an extension may be provided on flange 46 extending between arms 28 and out of the end of chamber 12 with a suitable device positioned between flange 20 and the extension to provide the necessary forces, fluid force applying mechanism 34 is preferred. Mechanism 34 includes a plunger 100 mounted by a press fit bushing 102 for reciprocable movement into and out of passageway 38. An enlarged cylindrical boss 4 is affixed on the end of plunger 100' providing one abutment for a helical spring 106 surrounding plunger 100 in engagement with bushing 102 and acting to bias plunger 100 into the retracted position.

A pressure cup 108 is affixed to the end of boss 102 and acts as a piston in sealing engagement with the wall of passageway 38. A fluid inlet 110 communicates with passageway 38 for the insertion of a pressurized fluid, such as air or liquid, to force piston 108 away from partition 42 thereby advancing plunger 100. It should be apparent that a fluid hose may be connected to inlet 110 and passed between arms 28 and over mounting means 32 to the exterior of pump 10 at which point it is attached to a suitable pressure source (not shown), An adaptor ring 111 is mounted intermediate the ends of plunger for cooperating or connecting the end of the pressure flange (nearest the point of insertion) of the stuffing box of the pump (not shown). Plunger 100 inserts through stufiing box of pump (not shown) and a hose through which pressurized fluid may be supplied is attached to inlet 110.

During the insertion of liner puller 22 into chamber 12, point 112 will be received in the end of the piston rod which has preferably been moved to its rearmost position. After arms 28 have been outwardly pivoted into engagement with liner 16, suitable pressurized fluid is delivered through inlet to extend plunger 100 thereby creating a force axial with respect to support 24 as shown by the arrow in FIG. 1.

The operator then activates suitable control means of the liquid system to deliver pressurized liquid through inlet 110 to extend plunger 100 in a conventional manner. Since adaptor ring 111 is in contact with the end of the pressure flange of the stuffing box of pump (not shown), it will be evident that a sufficient stationary shoulder is provided to force liner puller 22 in the direction shown by the arrow in FIG. 1. Since arms 28 are in engagement with pump liner 16, it will be evident that liner 16 will also be slidably removed from pump casing 12.

THE ALTERNATIVE EMBODIMENT Reference is now made to FIGS. 7 through 10 wherein like numerals refer to like elements throughout the several views.

It will first be noted that the embodiment of FIG. 7 is somewhat simplified with respect to the foregoing embodiment but that the same inventive concept and basic structure is embodied therein.

The device 200- embodied in FIG. 7 includes a central elongate portion including a hollow externally threaded member 202 secured by a weld 204 to an enlarged cylinder head member 206 which includes a threaded extension 208. Threadably received on this extension 208 is a hydraulic cylinder 2 10. A cap 213, which has an opening therethrough, is threadably received on the distal end of the cylinder 210. A piston member 212 is reciprocably received in the cylinder 210. This piston member and the associated components thereof is shown in greater detail in FIG. 8 to which reference is now made.

The piston 212 includes an elongate shank portion 214 and a head portion 216, the latter being provided with a plurality of ring grooves 218 for receiving piston rings 220, the latter being shown in FIG. 7. The rear end of the shank portion 214 has a diminished circumference area shown at 222 and an annular groove therein for receiving a keeper 224. The keeper 224 holds an annular engaging disc 226 on the end of the shank portion 222.

A very important facet of this embodiment of the invention is the provision of a passageway 228 extending entirely through the piston 212, the outer end of the passageway being threaded as at 230. Received in the hollow center of the member 202 is an elongate rod 232 which may be reciprocably slid inwardly and outwardly in the center of member 202 and is knurled at the distal end as shown at 234. A collar 236 is secured as by a weldment 238 proximate the distal end of the reciprocable rod 232. A plurality of arms 240, 242 and 244 are pivotally secured by means of pins 246, 248 and 250 between pairs of apertured extensions 252a and 252b, 254a and 25411 and 256a and 2561). It will be seen that the arms can pivot outwardly at any desired angle with respect to the axis of the rod 232. A sleeve 258 is threadably received on the threaded exterior of the hollow elongate member 202. Of course, the position of the sleeve 258 on the hollow member 202 may be adjusted at any point simply by rotating the hollow member in the sleeve. The arms 240, 242 and 244 are received between apertured extensions 260a and 260b, 262a and 262b and 264a and 264b, 26217 and 264-17 not being shown. The arms are held between the extensions by means of keeper pins 266, 268 and 270 and are permitted to slide between the keeper pins and the sleeve. As best illustrated in FIG. 10, the sleeve includes three portions 272, 274 and 276, which are arcuate convexly against which the arms rest. These portions form pivot points for the arms. Each of the arms is provided with an engaging lip 280 for engaging the end of a liner.

The operation of this embodiment of the device is generally the same as that previously described with respect to the first embodiment of the invention. The operation will, however, be briefly described for purposes of continuity and clarity. First, the inside diameter of the liner to be removed is determined. Conventionally, these liners vary from about five inches inside diameter to eight or more inches diameter. Let us assume, for purposes of ilustration, that a six inch diameter liner is in the pump and it is desired to remove this liner. The rod 232 is moved inwardly in the member 202 to its maximum inward position. The central member is rotated and, as a result of this rotation and the threaded engagement of the sleeve 258 of the threaded exterior 202, the sleeve 258 moves outwardly along the member 202. This causes the arms 240, 242, 244 to move outwardly in a pivotal fashion. Once the arms have been moved out such that the points 278 and the engaging lip 280, are just outside the end and edge of the liner (nearest the point of insertion) shown in FIG. 7 and all of the arms lie on a circle having a diameter of six inches then the rotation is ceased and the tool is prepared for use. At this point all of the arms extend outwardly too far and it is not possible to slip the liner puller into the liner. In order to position the liner puller in the liner, the rod 232 is reciprocably moved outwardly causing the ends of the arms to pivot inwardly because of the relationship of the pivot point on the end of the arm and the pivot point intermediate of the arm. This position is shown in FIG. 7. The piston and piston rod of the pump are removed, as is conventional practice. The liner puller is then inserted through the liner until the point 278 and the engaging lip 280 are just beyond the end of the liner (opposite the point of insertion) and the annular engaging disc 226 has made contact with the pressure flange of the stufliing box of the pump (not shown), and the rod 232 is pushed inwardly thereby causing the arms to expand outwardly to the desired diameter. A hydraulic hose is connected by any threaded coupling to the threaded end 230 of the passageway 228 in the piston 212 and a hydraulic pump is secured at the other end of this hydraulic line. This connection obviates the necessity of stringing a hydraulic hose or conduit through the liner. The inside end of the liner puller is easily accessible in most pumps and in most engines. Pumps of the type for 'which this invention is designed, preferably, are those pumps made by Continental-Emsko Company, a division of Youngstown Sheet and Tube Company, Dallas, Tex., and are described as Models DA/700, DB/700, DA/ 850, and D/1000- Mud Pumps. Of course, the present liner puller can be used with nearly any type of pump whether it be a mud pump or not or a reciprocating engine wherein a liner is utilized. In common usage, the annular engaging disc 226 rests against the end of the pressure flange (nearest the point of insertion) of the stufling box of the pump, and as the hydraulic fluid is pumped from the pump through the passageway 228 into the space between the end of the piston 212 and the end of the cylinder 208, the piston moves outwardly. As it moves outwardly it causes the entire liner puller assembly to move in a direction opposite the direction of insertion since the annular engaging disc engages the fixed pressure flange of the stuffing box of the pump. As the liner puller moves out slowly and evenly the lip 280 of each arm 240, 242, 244 engages the end and edge of the liner, and according to the pumping of the fluid, the liner is forced to move along and with and in the same direction as the liner puller.

It will be apparent from the foregoing that the invention just described offers many and significant advantages over the pullers of the prior art.

It will be appreciated also that variations from the embodiments shown may be made without departing from the scope and spirit of the invention. Merely exemplary of the types of departures which can be made from the precise embodiment disclosed is that four or more or less than three arms may be utilized according to the size of the liner to be pulled and other considerations. Of course, other modifications may be made without departing from the scope of the invention as defined in the following claims.

I claim:

1. A device for pulling a liner from a reciprocating pump of the type having a cylinderical pressure chamber and a frictionally held liner therein comprising an elongate central support for placement adjacent the axis of the liner;

a plunger, mounted on the support, for telescopic movement therewith;

a plurality of arms spaced about the support and extending generally in the direction thereof, having liner end engaging means on the end thereof;

means mounting each of the arms on the support for slidable movement upon movement of the plunger with respect to the support;

means mounting each of the arms on the support and the plunger for outward pivotal movement upon insertion of the plunger with respect to the support for placing the liner end engaging means in contact with the liner end;

means for selectively applying a force between the support and the pump for removing the liner;

said pivotal mounting means including first means pivotally mounting each arm on the plunger and second means, integral with the slidable mounting means, pivotally mounting each arm on the support, said slidable mounting means and the second pivotal mounting means being adjustably mounted on the support.

2. The liner puller of claim 1 further including a plurality of indicia operatively arranged on the device for designating the spread of the liner engaging means.

3. The liner puller of claim 1 wherein the slidable mounting means and the second pivotal mounting means including a block forming a plurality of slots for receiving each of the arm; and

a rocker, pivotally mounted in each slot about an axis transverse to the arm, having a central opening slidably receiving the arm.

4. A device for pulling a liner from a reciprocating pump of the type having a cylindrical pressure chamber and a frictionally held liner therein comprising an elongate central support for placement adjacent the axis of the liner;

a plunger, mounted on the support, for telescopic movement therewith;

a plurality of arms spaced about the support and extending generally in the direction thereof, having liner engaging means 011 the end thereof;

means mounting each of the arms on the support for slida'ble movement upon movement of the plunger with respect to the support;

means mounting each of the arms on the support and the plunger for outward pivotal movement upon insertion of the plunger with respect to the support for placing the liner engaging means in contact with the end and edge of a liner;

means for selectively applying a force between the support and the pump for removing the liner;

said force applying means including fluid means for selectively extending the support with respect to the plunger.

5. A liner puller comprising:

an elongate central portion which includes non-communicating elongate blind cylindrical openings in each end thereof;

a piston received in one end opening;

means for supplying pressurized fluid into the lastnamed opening for selectively reciprocating the piston in said opening;

a rod reciprocably received in the other end opening;

a plurality of liner engaging arms normally lying along the length of the central portion;

means pivotally securing one end of each of the arms to the rod;

collar means on the central portion slidably and pivotally receiving an intermediate portion of each of the arms; and

means for adjusting the collar means longitudinally on the central portion for thereby fixing the angular relation of the arms relative to the central portion;

whereby the arms may be fixed at a predetermined angle by selective positioning of the collar means on the central portion, the angle of the arms relative to the central portion may be reduced for inserting the puller in a liner and returned to said predetermined angle for engaging the end of the liner by reciprocation of the rod, and the puller and the liner may be removed by moving the central portion of the liner puller relative to the piston by forcing pressurized fluid into the one end opening of the piston.

6. The invention of claim 5 wherein the means for supplying pressurized fluid includes a passage longitudinally through the piston.

7. The invention of claim 6 wherein the means for adjusting the collar means includes means threadably engaging the collar means on the central portion.

References Cited UNITED STATES PATENTS 2,487,902 11/1949 Stout 29-252 2,491,682 12/1949 Muhbach 294-97 2,924,005 2/ 1960 Wilson 29--283 ROBERT C. RIORDON, Primary Examiner G. F. GRAFEL, Assistant Examiner 

